Dynamic time step control

This model extension is available from WaSiM model version 7.9.x. It ensures an improved accuracy of the calculation of soil water movement after Richards in compliance with the COURANT-condition. The Courant condition says that the numerical flow simulation will only remain stable if the calculation time step is smaller than the propagation step. In other words, water must not flow through more than a numeric soil layer. This is required because of the explicite solution algorithm of the Richards-equation

To make sure the Courant-Consition is met, the length of time step is automatci adjusted depending on the actual hydraulic conductivity of the soil layers. SInce there may be multiple layers with different thickness and differen hydraulic conductivities, the minimum value of all condition checks is used.

Detailed information on the implemented time-step control section contains the dynamic timestep control in the WaSiM model documentation.

Detailed information on the implemented time-step control can be found in section Dynamic time step control in the WaSiM model documentation.